Propeller blade, propeller and vehicle provided with such a propeller

Abstract

The present invention relates to a blade (9) for a propeller (5), formed by at least three sections (23a, 23b, 23c) extending consecutively directly one after the other from a first end (E1) of the blade (9) forming a blade root to a second end (E2) of the blade (9) forming a blade tip, the pitch angle of each section (23b, 23c) directly following a preceding section (23a, 23b) being at least 5 degrees lower than the pitch angle of the preceding section (23a, 23b). The invention also relates to a propeller (5) comprising at least two such blades (9), as well as to a vehicle, preferably a marine vehicle, more preferably a ship, comprising such a propeller (5), and a motor configured to drive the propeller (5), wherein the motor is preferably an electric motor.

Description

[0001] DESCRIPTION

[0002] TITLE: Propeller blade, propeller and vehicle equipped with such a propeller

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to a blade for a propeller, preferably for a propeller for hydrodynamic propulsion. The present invention also relates to a propeller, preferably for hydrodynamic propulsion, provided with at least two such blades. The invention finally relates to a vehicle, preferably a marine vehicle, more preferably a ship, provided with such a propeller.

[0005] STATE OF THE ART

[0006] Most propellers currently available on the market are multi-blade propellers, comprising a hub pivoting around an axis of rotation, from which the blades extend radially. The blades are located on the hub and are angularly regularly distributed on the hub around this axis of rotation.

[0007] A propeller can thus be a driving propeller, for example mounted on a vehicle such as a boat or an aircraft, or a receiving propeller, for example mounted on a turbine, a wind turbine or a wind generator.

[0008] The shape of the blades of existing propellers, which are generally arranged relative to each other according to the screw principle when they are intended for use in water, creates a depression on the extrados face, which is generally a convex face, and an overpressure on the intrados face, which is generally a concave face. The water is then ejected, thus creating thrust.

[0009] Document US 2012 / 0114498 A1 describes a fan structure comprising a hub and a plurality of blades, in which each blade may be formed from three sections which extend successively from the root of the blade to its tip.

[0010] However, most available propellers do not offer optimal performance, so they require the use of powerful motors, which cause high energy consumption.

[0011] Thus, particularly in liquid environments, most available propellers have turbulence problems, which are due in particular to the hydrodynamic disturbances generated by the blades, as well as to the "recoil" caused in particular by the mutual influence of the blades on each other.

[0012] Thus, for most existing propellers, the rotation of the propeller causes turbulence that can disrupt the flow of water, which reduces the efficiency of the propeller, causes vibrations and noise.

[0013] STATEMENT OF THE INVENTION

[0014] The present invention aims to overcome all or part of the drawbacks cited above.

[0015] The invention aims in particular to provide a propeller blade with improved performance, while generating less vibration and noise.

[0016] According to a first aspect, the invention proposes a blade for a propeller, preferably for a propeller for hydrodynamic propulsion, remarkable in that it is formed by at least three sections extending successively directly after one another from a first end of the blade forming a blade root to a second end of the blade forming a blade tip, the pitch angle of each section directly following a preceding section being at least 5 degrees lower, preferably at least 10 degrees lower, than the pitch angle of the preceding section.

[0017] Thus, such a propeller blade makes it possible to reduce the disturbances generated by it, which allows the propeller equipped with such blades to have improved performance while generating less vibration and noise. More precisely, the use of at least three sections with such pitch angles offset relatively to each other makes it possible to reduce the disturbances generated, in particular hydrodynamic disturbances.

[0018] By "section directly following a preceding section" is meant a section directly following a preceding section in the direction from the first end of the blade forming the blade root to the second end of the blade forming the blade tip. Thus, advantageously, these two sections are adjacent. Furthermore, advantageously, no transition element is in particular arranged between the section in question and the preceding section.

[0019] The blade according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations: - The blade is formed by exactly three sections. Thus, the design and manufacture of the blade are simplified.

[0020] - The sections extend successively directly after each other following a leading edge of the blade.

[0021] - Each section has a predetermined pitch angle. This simplifies the design and manufacture of the blade.

[0022] - All the setting angles are located in a single angular sector less than or equal to 45 degrees, preferably less than or equal to 35 degrees. This ensures optimal efficiency improvement.

[0023] - The pitch angle of each section is defined in relation to a plane of rotation of the blade, in other words the plane of rotation of the propeller carrying the blade, the plane of rotation being orthogonal to the axis of rotation of the propeller.

[0024] - For each section directly following a preceding section, the pitch angle of the section directly following the preceding section is less than the pitch angle of the preceding section by a value between 5 degrees and 30 degrees, preferably by a value between 10 degrees and 30 degrees, more preferably by a value between 10 degrees and 25 degrees, even more preferably by a value between 10 degrees and 20 degrees, and most preferably by a value between 10 degrees and 15 degrees. Thus, the improvement in efficiency is optimal. In particular, a difference in pitch angle of at least 10 degrees between two successive sections makes it possible to significantly increase the hydrodynamic performance of the blade.

[0025] - For each section directly following a preceding section, the minimum chord length of the section directly following the preceding section differs by at least 10% from the maximum chord length of the preceding section, preferably differs by at least 30% from the maximum chord length of the preceding section. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0026] - The trailing edge is included in a plane, preferably in a plane including the axis of rotation and orthogonal to the plane of rotation, the plane of rotation itself being orthogonal to the axis of rotation. Thus, the design and manufacture of the blade are simplified.

[0027] - For each section directly following a preceding section, the minimum chord length of the section directly following the preceding section is at least 10% greater than the maximum chord length of the preceding section, preferably at least 30% greater than the maximum chord length of the preceding section. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0028] - For each section directly following a preceding section, the maximum thickness of the section directly following the preceding section is at least 10% less than the maximum thickness of the preceding section, preferably at least 20% less than the maximum thickness of the preceding section. Thus, the mass of the blade is reduced.

[0029] - The sections are gradually offset from each other. This improves efficiency.

[0030] - The blade has an intrados face and an extrados face extending between the leading edge and a trailing edge.

[0031] - For each section directly following a preceding section, the section directly following the preceding section is flush with the preceding section either only on the intrados side over a major part of the intrados face leading to the leading edge, or only on the extrados side over a major part of the extrados face leading to the leading edge. Thus, the disturbances generated by the blade are reduced, while maintaining improved efficiency.

[0032] - The leading edge is straight on each section, preferably completely straight. This reduces the disturbances generated by the blade.

[0033] - Each section directly following a previous section is offset by a predetermined angle around a longitudinal axis of the blade relative to the previous section. This simplifies manufacturing.

[0034] - The blade is monolithic. Thus, the structural integrity of the blade is optimized, and its manufacture is simplified. Preferably, the blade is obtained by molding or welding. Alternatively, the sections of each blade are independent parts, in other words separate parts, and are fixed to each other to form the blade, preferably are mechanically fixed. Thus in each blade, each section directly following a preceding section is fixed to this preceding section. The modularity of the sections is then improved, and the costs of the blade are reduced because the manufacture of each section is simplified. According to a second aspect, the invention provides a propeller, preferably for hydrodynamic propulsion, comprising a hub pivoting about an axis of rotation, hub from which extend at least two blades as previously described, the blades being angularly regularly distributed from the hub about the axis of rotation.

[0035] Thus, such a propeller has improved efficiency while generating less vibration and noise. More specifically, the use of at least two blades as previously described allows for better circulation of the fluid through the propeller during rotation of the propeller around the axis of rotation. Indeed, the difference in pitch angle between the sections reduces the disturbances generated by the propeller, in particular hydrodynamic disturbances, as well as the propeller recoil coefficient. For example, when the propeller is a pusher propeller, each blade pushes the fluid back without causing negative pressure or overpressure that would be detrimental to the thrust.

[0036] The propeller according to the invention is advantageously and optionally supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

[0037] - The blades extend radially outward from the hub, relative to the axis of rotation.

[0038] - The angularly regularly distributed blades are arranged every 360° / Z around the axis of rotation, with Z the number of propeller blades.

[0039] - The blades are identical. This reduces vibrations and improves propeller efficiency.

[0040] - The blades have a fixed pitch. This simplifies the operation of the propeller.

[0041] - The blades have variable pitch. This makes it possible to further optimize the propeller's efficiency.

[0042] - The propeller has exactly three, four, five, six, seven, or eight blades. Using this number of blades is optimal for hydrodynamic propulsion, especially for marine vehicles such as ships.

[0043] - The hub is cylindrical. This limits the hub's interference with the blades. - The propeller is monolithic. This optimizes the propeller's structural integrity and simplifies its manufacturing.

[0044] - The propeller is made of plastic, metal or wood, for example bronze or a composite material based on a polymer reinforced with fibers, the fibers being for example glass or carbon fibers. The use of such materials makes it possible to adapt the material of the propeller to its use. For example, a bronze propeller is particularly suitable for mounting on a large tonnage vessel of the ship type, such as a cargo ship, a container ship, a supertanker or an LNG carrier.

[0045] According to a third aspect, the invention also provides a vehicle, preferably a marine vehicle, preferably a boat, more preferably a ship, comprising a propeller as previously described and a motor configured to drive the propeller, the motor preferably being an electric motor.

[0046] Indeed, the propeller according to the invention is particularly suitable for being mounted on a vehicle, preferably a marine vehicle such as a boat, in particular a ship. Preferably, the use of an electric motor makes it possible to reduce the noise as well as the vibrations transmitted to the propeller, and consequently makes it possible to reduce the vibrations of the propeller itself during its drive.

[0047] DESCRIPTION OF FIGURES

[0048] Other characteristics, aims and advantages of the invention will emerge from the detailed description below, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings, given as non-limiting examples and in which:

[0049] - figure 1 is a schematic side view of a vehicle comprising a propeller according to one embodiment;

[0050] - figure 2 is a schematic front view of a propeller according to one embodiment;

[0051] - Figure 3 is a schematic top view of a blade of the propeller shown in Figure 2;

[0052] - figure 4 is a schematic front view of a propeller according to a first variant embodiment;

[0053] - figure 5 is a schematic top view of a blade of a propeller according to a second variant embodiment.

[0054] Throughout the figures, similar elements are designated by identical references. DETAILED DESCRIPTION OF THE INVENTION

[0055] Figure 1 schematically represents an embodiment of a vehicle 1, which is preferably a marine vehicle, preferably a boat, more preferably a ship. Alternatively, according to a variant not shown, the vehicle 1 may be an aerial vehicle such as an aircraft or a drone.

[0056] Vehicle 1 has an engine 3 and a propeller 5.

[0057] Motor 3 is configured to drive propeller 5. Preferably, motor 3 is an electric motor.

[0058] Preferably, the propeller 5 is a propeller for hydrodynamic propulsion. The propeller 5 is thus configured to be driven in rotation in the water by the motor 3.

[0059] Advantageously, the propeller 5 is monolithic. The propeller 5 is thus formed from a single block, in a single piece.

[0060] Preferably, the propeller 5 is made of plastic, metal or wood. The propeller 5 is preferably made of bronze or a composite material based on a polymer reinforced with fibers. Advantageously, the fibers are glass or carbon fibers.

[0061] Advantageously, the propeller 5 comprises a hub 7 from which at least two blades 9 extend. Thus, the hub 7 supports the blades 9. The hub 7 pivots about an axis of rotation X. Thus, the propeller 5 also pivots about the axis of rotation X.

[0062] Advantageously, the axis of the motor shaft 3 coincides with the axis of rotation X.

[0063] Preferably, the hub 7 is cylindrical.

[0064] Figure 2 schematically represents an embodiment of a propeller 5, in projection onto a plane of rotation P of the propeller 5, the plane of rotation P being orthogonal to the axis of rotation X of the propeller 5.

[0065] According to the embodiment shown in Figure 2, the propeller 5 comprises exactly three blades 9. Alternatively, according to variants not shown, the propeller 5 comprises exactly four, five, six, seven or eight blades 9.

[0066] Advantageously, each blade 9 is monolithic. Preferably, each blade 9 is obtained by molding or by welding. Preferably, the blades 9 are identical.

[0067] Preferably, the blades 9 have a fixed pitch. Alternatively, according to a variant not shown, the blades have a variable pitch. Advantageously, according to this variant not shown, the blades are pivotally attached to the hub, each blade being configured to pivot selectively about a longitudinal axis of the blade in order to adjust the pitch of the blade.

[0068] Advantageously, the blades 9 are angularly regularly distributed from the hub 7 around the axis of rotation X. In other words, the angularly regularly distributed blades 9 are arranged every 360° / Z around the axis of rotation X, with Z the number of blades 9 of the propeller 5. In the embodiment shown in Figure 2, the propeller 5 comprising three blades 9, Z is therefore equal to 3. The three blades 9 are arranged every 360° / 3 = 120° around the axis of rotation X. For example, in a rotation position of the propeller 5 around the axis of rotation X, one blade 9 is arranged at 120°, one blade 9 is arranged at 240°, and one blade 9 is arranged at 360°.

[0069] Similarly, according to the variants not shown in which the propeller 5 comprises four, five or six blades 9, when the propeller 5 comprises four blades 9, the four blades 9 are arranged every 90° around the axis of rotation X, when the propeller 5 comprises five blades 9, the five blades 9 are arranged every 72° around the axis of rotation X, and when the propeller comprises six blades 9, the six blades 9 are arranged every 60° around the axis of rotation X.

[0070] Preferably, the blades 9 extend radially outward from the hub 7, relative to the axis of rotation X.

[0071] Advantageously, the hub 7 comprises a notch 13 extending radially on either side of the axis of rotation X. Such a notch 13 makes it possible to transmit torque simply and safely from the motor 5 to the hub 7, via a motor shaft. The motor shaft then comprises a rib complementary to the notch 13.

[0072] Advantageously, as shown in Figure 2 and / or in Figure 3, each blade 9 comprises a leading edge 15 and a trailing edge 17 delimiting between them an intrados face 19 and an extrados face 21.

[0073] Advantageously, each blade 9 is formed by a plurality of sections 23a, 23b, 23c extending successively directly one after the other from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip. Preferably, each blade 9 is formed by at least three sections 23a, 23b, 23c extending successively directly one after the other from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0074] Alternatively to the feature that each blade 9 is monolithic, the sections 23a, 23b, 23c of each blade 9 are independent parts, in other words separate parts, and are fixed to each other to form the blade 9, preferably are mechanically fixed. Thus in each blade 9, each section 23b, 23c directly following a preceding section 23a, 23b is fixed to this preceding section 23a, 23b.

[0075] Preferably, the sections 23a, 23b, 23c extend along the leading edge 15 of the blade 9.

[0076] Advantageously, the intrados face 19 and / or the extrados face 21 may comprise one facet per section 23a, 23b, 23c. Preferably, the adjacent facets of the intrados face 19 and / or the adjacent facets of the extrados face are concurrent only at the leading edge 15.

[0077] Preferably, each blade 9 is formed by exactly three sections 23a, 23b, 23c.

[0078] Advantageously, the setting angle a2, a3 of each section 23b, 23c directly following a preceding section 23a, 23b is at least 5 degrees lower, preferably at least 10 degrees lower, than the setting angle a1, a2 of the preceding section 23a, 23b.

[0079] Preferably, each section 23a, 23b, 23c has a predetermined setting angle a1, a2, a3.

[0080] Advantageously, all of the setting angles a1, a2, a3 are located in a single angular sector less than or equal to 45 degrees, preferably less than or equal to 35 degrees.

[0081] The pitch angle a1, a2, a3 of each section 23a, 23b, 23c is defined relative to a plane of rotation P of the blade 9, in other words the plane of rotation P of the propeller 5 carrying the blade 9, the plane of rotation P being orthogonal to the axis of rotation X of the propeller 5.

[0082] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the setting angle a2, a3 of each section 23b, 23c directly following the preceding section 23a, 23b is less than the setting angle a1, a2 of the preceding section 23a, 23b by a value between 5 degrees and 30 degrees, preferably by a value between 5 degrees and 20 degrees, more preferably by a value between 5 degrees and 15 degrees.

[0083] For example, as shown in Figure 3, the pitch angle a2 of section 23b is 15 degrees less than the pitch angle a1 of section 23a, and the pitch angle a3 of section 23c is 5 degrees less than the pitch angle of section 23b.

[0084] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the minimum length of the chord of the section 23b, 23c directly following the preceding section 23a, 23b differs by at least 10% from the maximum length of the chord of the preceding section 23a, 23b, preferably differs by at least 30% from the maximum length of the chord of the preceding section 23a, 23b.

[0085] Preferably, for each section 23b, 23c directly following a preceding section 23a, 23b, the minimum length of the chord of the section 23b, 23c directly following the preceding section 23a, 23b is at least 10% greater than the maximum length of the chord of the preceding section 23a, 23b, preferably is at least 30% greater than the maximum length of the chord of the preceding section 23a, 23b.

[0086] Advantageously, for each section 23b, 23c directly following a preceding section 23a, 23b, the maximum thickness of the section 23b, 23c directly following the preceding section 23a, 23b is at least 10% less than the maximum thickness of the preceding section 23a, 23b, preferably is at least 20% less than the maximum thickness of the preceding section 23a, 23b.

[0087] Preferably, the sections 23a, 23b, 23c are gradually offset from each other.

[0088] Advantageously, the leading edge 15 is rectilinear on each section 23a, 23b, 23c.

[0089] Figure 4 schematically represents a first variant embodiment of the propeller 5, in projection onto the plane of rotation P orthogonal to the axis of rotation X of the propeller 5.

[0090] The propeller 5 according to this first embodiment variant differs from the propeller 5 previously described and represented in particular in FIG. 2 in the following.

[0091] Advantageously, as shown in Figure 4, the leading edge 15 is completely rectilinear. Preferably, each blade 9 is such that the adjacent sections 23a-23b, 23b-23c are flush with each other either only on the side of the intrados face 19 over a major portion of the intrados face 19 leading to the leading edge 15, or only on the side of the extrados face 21 over a major portion of the extrados face 21 leading to the leading edge 15.

[0092] In other words, for each section 23b, 23c directly following a preceding section 23a, 23b, the section 23b, 23c directly following the preceding section 23a, 23b is flush with the preceding section 23a, 23b either only on the side of the intrados face 19 over a major part of the intrados face 19 leading to the leading edge 15, or only on the side of the extrados face 21 over a major part of the extrados face 21 leading to the leading edge 15.

[0093] As shown in Figure 4, the offset of the sections 23a, 23b, 23c relative to each other is thus achieved by an offset on the side of the intrados face 19. Thus, for each section 23b, 23c directly following a preceding section 23a, 23b, the section 23b, 23c directly following the preceding section 23a, 23b is flush with the preceding section 23a, 23b only on the side of the extrados face 21 over a major portion of the extrados face 21 leading to the leading edge 15.

[0094] Preferably, as shown in Figure 4, the trailing edge 17 is included in a plane F, preferably in a plane F comprising the axis of rotation X and orthogonal to the plane of rotation P, the plane of rotation P itself being orthogonal to the axis of rotation X.

[0095] Figure 5 schematically represents a top view of a blade 9 of a propeller 5 according to a second variant embodiment.

[0096] The propeller 5 according to this second embodiment variant differs from the propeller 5 previously described and represented in particular in FIG. 2 in the following.

[0097] Advantageously, each blade 9 is formed by a plurality of sections 23a, 23b, 23c extending successively directly one after the other along the longitudinal axis L of the blade 9 from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip.

[0098] Preferably, each blade 9 is formed by at least three sections 23a, 23b, 23c extending successively directly one after the other along the longitudinal axis L of the blade 9 from a first end E1 of the blade 9 forming a blade root to a second end E2 of the blade 9 forming a blade tip. Advantageously, the longitudinal axis L extends radially relative to the axis of rotation X.

[0099] Preferably, the longitudinal axis L is orthogonal to the axis of rotation X of the propeller 5 and is parallel to the plane of rotation P. More preferably, the longitudinal axis L extends orthogonally and radially relative to the axis of rotation X. In other words, the longitudinal axis L extends perpendicular to the axis of rotation X.

[0100] Advantageously according to this second embodiment variant, for each section 23b, 23c directly following a preceding section 23a, 23b, the setting angle a2, a3 of each section 23b, 23c directly following the preceding section 23a, 23b is less than the setting angle a1, a2 of the preceding section 23a, 23b by a value between 5 degrees and 30 degrees, preferably by a value between 10 degrees and 30 degrees, more preferably by a value between 10 degrees and 25 degrees, even more preferably by a value between 10 degrees and 20 degrees, or even more preferably by a value between 10 degrees and 15 degrees.

[0101] Advantageously, each section 23b, 23c directly following a preceding section 23a, 23b is offset by a predetermined angle around the longitudinal axis L of the blade 9 relative to the preceding section 23a, 23b.

[0102] Preferably, the sections 23a, 23b, 23c are aligned along the longitudinal axis L and have only a predetermined angular offset around the longitudinal axis L relative to each other.

[0103] Thus, according to this second embodiment, the section 23b is offset by an angle a2 - a1 around the longitudinal axis L relative to the section 23a, and the section 23c is offset by an angle a3 - a2 around the longitudinal axis L relative to the section 23a.

[0104] Advantageously, all of the setting angles a1, a2, a3 are located in a single angular sector less than or equal to 45 degrees.

[0105] For example, as shown in Figure 5, the setting angle a1 of the section 23a is equal to 13°, the setting angle a2 of the section 23b is equal to 29°, and the setting angle a3 of the section 23c is equal to 55°.

[0106] More generally, the blade 9 and / or the propeller 5 previously described can be configured to be mounted on a hydraulic turbine, a hydro turbine, a wind turbine, a turbomachine. The invention is not limited to the embodiments and variants presented and other embodiments will become clear to those skilled in the art. It is in particular possible to combine the embodiments and variants with each other.

Claims

CLAIMS 1. Blade (9) for a propeller (5), preferably for a propeller for hydrodynamic propulsion, the blade (9) being formed by at least three sections (23a, 23b, 23c) extending successively directly one after the other from a first end (E1) of the blade (9) forming a blade root to a second end (E2) of the blade (9) forming a blade tip, characterized in that the pitch angle a2, a3 of each section (23b, 23c) directly following a preceding section (23a, 23b) is at least 5 degrees lower than the pitch angle a1, a2 of the preceding section (23a, 23b).

2. Blade (9) according to claim 1, in which, for each section (23b, 23c) directly following a preceding section (23a, 23b), the pitch angle a2, a3 of the section (23b, 23c) directly following the preceding section (23a, 23b) is less than the pitch angle a1, a2 of the preceding section (23a, 23b) by a value between 10 degrees and 30 degrees.

3. Blade (9) according to claim 1 or 2, wherein, for each section (23b, 23c) directly following a preceding section (23a, 23b), the minimum length of the chord of the section (23b, 23c) directly following the preceding section (23a, 23b) differs by at least 10% from the maximum length of the chord of the preceding section (23a, 23b), preferably differs by at least 30% from the maximum length of the chord of the preceding section (23a, 23b).

4. Blade (9) according to claim 3, in which, for each section (23b, 23c) directly following a preceding section (23a, 23b), the minimum length of the chord of the section (23b, 23c) directly following the preceding section (23a, 23b) is at least 10% greater than the maximum length of the chord of the preceding section (23a, 23b), preferably is at least 30% greater than the maximum length of the chord of the preceding section (23a, 23b).

5. Blade (9) according to any one of claims 1 to 4, in which, for each section (23b, 23c) directly following a preceding section (23a, 23b), the maximum thickness of the section (23b, 23c) directly following the preceding section (23a, 23b) is at least 10% less than the maximum thickness of the preceding section (23a, 23b), preferably is at least 20% less than the maximum thickness of the preceding section (23a, 23b).

6. Blade (9) according to any one of claims 1 to 5, in which the sections (23a, 23b, 23c) are gradually offset relative to each other.

7. Blade (9) according to any one of claims 1 to 6, which has a lower surface face (19) and an upper surface face (21) extending between the leading edge (15) and a trailing edge (17), and in which, for each section (23b, 23c) directly following a preceding section (23b, 23c), the section (23b, 23c) directly following the preceding section (23a, 23b, 23c) is flush with the preceding section (23b, 23c) either only on the side of the lower surface face (19) over a major part of the lower surface face (19) leading to the leading edge (15), or only on the side of the upper surface face (21) over a major part of the upper surface face (21) leading to the leading edge (15).

8. Blade (9) according to any one of claims 1 to 7, in which the leading edge (15) is rectilinear on each section (23a, 23b, 23c), preferably is completely rectilinear.

9. Blade (9) according to any one of claims 1 to 8, in which each section (23b, 23c) directly following a preceding section (23a, 23b) is offset by a predetermined angle around a longitudinal axis (L) of the blade (9) relative to the preceding section (23a, 23b).

10. Propeller (5), preferably for hydrodynamic propulsion, comprising a hub (7) pivoting about an axis of rotation (X), hub (7) from which at least two blades (9) according to any one of claims 1 to 9 extend, the blades (9) being angularly regularly distributed from the hub (7) about the axis of rotation (X).

11. Vehicle (1), preferably marine vehicle, more preferably ship, comprising a propeller (5) according to claim 10 and a motor (3) configured to drive the propeller (5), the motor (3) preferably being an electric motor.

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